Tham khảo tài liệu 'new sat math workbook episode 2 part 1', ngoại ngữ, ngữ pháp tiếng anh phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Factoring and Algebraic Fractions 165 RETEST Work out each problem. Circle the letter that appears before your answer. 1. Find the sum of 2n and n. 5. Simplify ỷL A 3n 50 1 B n C 2 2n2 50 D 2n2 10 E 1 n 2 A 2 x x B y 2 x C y 3 x D y 3x 1 E 3x 1 2. Combine into a single fraction - - 3 3 I 6. 3 is equal to A x 3y y x 3 B y x 9 C 3y D x 3y E 2 x A 3 x B 3x23 x C x2 - x D 3x 1 E 3-X 3. Divide 8 by 2-X . 4 x 3 A 3 B -3 C 3 x - 2 D 3 2 x E none of these 3 I 5a3 4. Find an expression equivalent to I I 15a6 A b3 15a9 B b3 C 125a6 b3 D 125a9 b3 25a6 E 7. If a2 - b2 100 and a b 25 then a - b A 4 B 75 C -4 D -75 E 5 8. The trinomial x2 - 8x - 20 is exactly divisible by A x - 5 B x - 4 C x - 2 D x - 10 E x - 1 9. If 1 1 6 and 1 1 5 find -2 2 . a b a b a b A 30 B -11 C 61 D 11 E 1 10. If x - y 2 30 and xy 17 find x2 y2. A -4 B 4 C 13 D 47 E 64 166 Chapter 11 SOLUTIONS TO PRACTICE EXERCISES Diagnostic Test 1. C 2. D rb-- 3. B 5 cancel x 5 s. x 5 5 - x x 5 x 5 1 5 x 1 x 5 _ 3x2 3x2 3x2 27 x6 4. E Exercise 1 3x2 x y x 1. B 9x x y - 3 2 x 4 2 2. A 3 4 x 3 3x y . 3. E 1 y 3x regardless of the values of x and y as long as the denominator is not 0. b 4 b 3 b 4 4. C b 5 b 3 b 5 2 x 2y 2 1 5 D 6 x 2y _ 6 3 5. E Multiply every term by a. _ 7 _ 1 a 2 a 2 a b- a b a 1 2b 1 2 t bb 6. C Multiply every term by ab. b a 2ab 7. A x2 -y x y x -y 48 Substituting 16 for x y we have 16 x y 48 x y 3 8. D x y 2 x2 2xy y2 100 Substituting 20 for xy we have x 2 40 y2 100 x2 y2 60 9. D f 1 1 1 4 4 I _ . I . . 2 2 x y J x y J x y f 1 1 L __L l2 JI 4 J ỹ - 7 1 __1 1 0 T 77 8 x y 10. C x2 - x - 20 x - 5 x 4 Factoring and Algebraic Fractions 167 Exercise 2 Exercise 3 1. D 6x 5y 4 x y 2x 2x _ 6 x 5y - 4 x - y _ 2x 4y 2x 2x 2 x 2y x 2y 2x x 3c 3d 3 c d 2. D 3 -7 d2 3 c d c d 2a 3a _ 5a _ a 3. B ------- 10 10 2 4. A x F x 7 5 C 3b 10 - 4 7b 30b - 28b 4 10 40 _ 2b__b_ 40 20 5. 1. B Divide x2 and y3. 1 y 1 x3 y x 3 2. C c b- b c 3. C ax y a by x Divide y and x. y 4. D 4abc T .
